This invention relates to the class of devices for the administration of substances in a liquid medium and more particularly to a hand-held, finger-operated hypodermic syringe.
Various devices including the hypodermic syringe have been successfully employed over the past decades for the administration of substance into organs, animals, and human beings. The common spring consists of a needle, plunger, and barrel, and has proven satisfactory in that the damage sustained by the target due to the puncture is de minimis and the subsequent increase in pressure as a result of the liquid injection does not deleteriously affect the living tissue in the surrounding area. That is to say the surrounding tissue is usually able to sustain the increased pressure which pressure is proportional to that applied to the plunger. If the plunger is depressed with a quick swift push, the fluid is delivered at a high pressure. As the plunger is depressed in a jerky, uneven manner, the fluid pressure through the needle will fluctuate and be irregular. Although such actions will in most cases do little harm to the target, those suffereing from cardiovascular diseases or other diseases whose characteristics include the weakening of vessel walls must be treated with care. Accordingly, any substance applied to such patients must be done so that even pressure and maximum care be taken not to exascerbate the tissue near the area of the injection. Moreover, even through the hypodermic injection causes no permanent harm to patients without cardiovascular diseases, the irregular application of pressure or the excess of it can cause hematoma and is quite painful. In the laboratory many examples are also available to show the need to evenly apply liquid substances in a delicate manner.
When treating diseases with the characteristics cited above, or use of the device as previously stated, the application of a substance at high or fluctuating pressure as delivered by a hypodermic injection, may create undesirable stress on tissue in the immediate area or further degrade the walls of a system. As a matter of fact, serious thought is often given to the decision regarding whether or not an afflicted patient or a delicate organ should be subjected to the risk of the injection itself.
Accordingly, with the above drawbacks in mind, I have developed a device which is capable of evening the applied pressure during a hypodermic injection so as to reduce the risks of inflecting harm to a patient or organ. Moreover, I have invented an inexpensive hypodermic syringe device which is capable of indicating the amount of pressure provided to the patient in combination with a pressure relief mechanism.
It is, therefore, a primary object of the present invention to provide a hypodermic syringe device capable of indicating the amount of pressure applied through its needle and into the patient or organ.